A | B |
pseudostratified | a single layer of cells appearing as more than one layer because the nuclei occupy different positions in the cells |
stratified | arranged in layers |
keratinizing | forming keratin (hardening) |
non-keratinizing | not forming keratin |
columnar | elongated in shape |
epithelium | tissue type that covers all free body surfaces |
microvilli | tiny cylindrical process that extends from some epithelial cell membranes and increases membrane surface area |
goblet | an epithelial cell specialized to secrete mucus |
squamous | flat or platelike |
simple | one layer |
cuboidal | shaped like a cube |
tubules | small rounded processes that extend from the epithelial cell membranes |
cytoplasm | fluid and organelles that occupy the space between the cell membrane and nuclear envelope |
endoplasmic reticulum | comples of membranous structures within the cytoplasm |
hypertonic | solution that has a greater osmotic pressure than body fluids |
hypotonic | solution that has a lesser osmotic pressure than body fluids |
interphase | stage that occurs between mitotic divisions of a cell |
isotonic | solutin that has the same osmotic pressure as body fluids |
mitosis | process of cell division when threadlike chromosomes become visible within a cell |
phagocytosis | process by which a cell takes in solid particles |
pinocytosis | process by which a cell takes in tiny droplets of liquid |
ribosome | tiny spherical structure that consists of protein and RNA |
active transport | process that requires an expenditure of energy to move a substance across a cell membrane, usually against the concentrations gradient |
apoptosis | programmed death of a cell |
cell membrane | the selectively permeable outer boundary of a cell consisting of a phospholipid bilayer embedded with proteteins |
centrosome | cellular organelle consisting of two centrioles |
chromosome | rodlike structure that condenses from chromatin in a cell's nucleus during mitosis |
cytoskeleton | a shifting lattice arrangement of structural and contractile components distributed throughout the cell's cytoplasm consisting of microfilaments, microtubules, and larger filaments functioning in providing structural support and transport mechanism |
differentiation | cell specialization |
diffusion | random movement of molecules into smaller molecules that can be absorbed |
endocytosis | process by which a cell membrane envelops a substance and draws it into the cell in a vesicle |
equilibrium | a state of balance between two opposing forces |
exocytosis | transport of material out of a cell by means of a vesicle or sac that first engulfs the material and then is extruded through an opening in the cell membrane |
facilitated diffusion | diffusion in which carrier molecules transport substances across membranes from a region of higher concentration to a region of lower concentration |
filtration | movement of material through a membrane as a result of hydrostatic pressure |
golgi apparatus | an organelle that prepares cellular products for secretion |
lysosome | organelle that contains digestive enzymes |
mitochondria | an organelle in the cytoplasm that functions in transforming energy from glucose to ATP |
nucleolus | a small structure within the cell nucleus that contains RNA and proteins |
organelle | a part of a cell that performs a specialized function |
osmosis | diffusion of water through a selectively permeable membrane in response to a concentration gradient |
selectively permeable | a membrane that allows some molecules through but not others |
vesicle | membranous cytoplasm sac formed by infolding of the cell membrane |